Digital terrain models (DTMs) produced from multibeam
bathymetric data provide valuable base maps for marine geological
interpretations. These maps help define the geological variability of
the seafloor (one of the primary controls of benthic habitat
diversity); improve our understanding of the processes that control the
distribution and transport of bottom sediments, and the distribution of
benthic habitats and associated infaunal community structures; and
provide a detailed framework for future research, monitoring, and
management activities.
The bathymetric survey interpreted herein (National Oceanic and
Atmospheric Administration (NOAA) survey H11255) covers roughly 95 km2
of seafloor in southeastern Long Island Sound. This bathymetry has been
examined in relation to seismic reflection data collected concurrently,
as well as archived seismic profiles acquired as part of a
long-standing geologic mapping partnership between the State of
Connecticut and the U.S. Geological Survey (USGS). The objective of
this work was to use these acoustic data sets to interpret
geomorphological attributes of the seafloor, and to use these
interpretations to better understand the Quaternary geologic history
and modern sedimentary processes.

The multibeam data for was acquired in XTF (extended
Triton data format), recorded digitally through an ISIS data
acquisition system, and processed using CARIS HIPS (Hydrographic Image
Processing System) software for quality control, to incorporate sound
velocity and tidal corrections, and to produce base surfaces at two
resolutions: 1-m resolution in the shallower southeastern corner; 2-m
resolution over the remaining study area. Among other formats (.tif and
.asc), the data were exported in GeoZui format (.gutm) in UTM Zone 18.

Process_Date: Unknown

Source_Produced_Citation_Abbreviation:
h11255_1m.gutm

Source_Produced_Citation_Abbreviation:
h11255_2m.gutm

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Marc Moser

Contact_Organization: National
Oceanic and Atmospheric Administration

Contact_Position: Field Operations
Officer

Contact_Address:

Address_Type: mailing address

Address: 439 West York Street

City: Norfolk

State_or_Province: VA

Postal_Code: 23510

Country: USA

Contact_Voice_Telephone: (757)
441-6746

Contact_Electronic_Mail_Address:
marc.s.moser@noaa.gov

Process_Step:

Process_Description:

The GeoZui files were imported into Fledermaus and
exported as xyz files. The xyz files were moved to a Linux system where
they were cleaned to remove ASCII errors and combined (concatenated)
into one file at an optimal resolution of 2 m.

Source_Used_Citation_Abbreviation:
h11255_1m.gutm

Source_Used_Citation_Abbreviation:
h11255_2m.gutm

Process_Date: Unknown

Source_Produced_Citation_Abbreviation:
h11255_2mutm18_xyz.txt

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Seth Ackerman

Contact_Organization: U.S.
Geological Survey

Contact_Position: GIS Specialist

Contact_Address:

Address_Type: mailing and
physical address

Address: 384 Woods Hole Road

City: Woods Hole

State_or_Province: MA

Postal_Code: 02543

Country: USA

Contact_Voice_Telephone:
508-548-8700 x2315

Contact_Facsimile_Telephone:
508-457-2310

Contact_Electronic_Mail_Address:
sackerman@usgs.gov

Process_Step:

Process_Description:

SwathEd software, produced by the Ocean Mapping Group
at the University of New Brunswick, was used to create an ASCII grid
from the xyz text file and ArcCatalog was used to convert the ASCII
grid to a raster grid.

Source_Used_Citation_Abbreviation:
h11255_2mutm18_xyz.txt

Process_Date: Unknown

Source_Produced_Citation_Abbreviation:
bathy2m_utm18

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Seth Ackerman

Contact_Organization: U.S.
Geological Survey

Contact_Position: GIS Specialist

Contact_Voice_Telephone:
508-548-8700 x2315

Contact_Facsimile_Telephone:
508-457-2310

Contact_Electronic_Mail_Address:
sackerman@usgs.gov

Process_Step:

Process_Description:

A hill-shaded surface was generated from the grid
using 3D Analyst Tools with sun illumination from 0 degrees (a
direction parallel to most ship tracks to minimize artifacts) and an
angle 45 degrees above the horizon, and to vertically exaggerate the
surface 10x.

Source_Used_Citation_Abbreviation:
bathy2m_utm18

Source_Produced_Citation_Abbreviation:
hls10x360utm

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Seth Ackerman

Contact_Organization: U.S.
Geological Survey

Contact_Position: GIS Specialist

Contact_Voice_Telephone:
508-548-8700 x2315

Contact_Facsimile_Telephone:
508-457-2310

Contact_Electronic_Mail_Address:
sackerman@usgs.gov

Process_Step:

Process_Description:

The UTM bathymetric grid was reprojected into
geographic in ArcCatalog.

Source_Used_Citation_Abbreviation:
hls10x360utm

Source_Produced_Citation_Abbreviation:
hls10x360geo

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Seth Ackerman

Contact_Organization: U.S.
Geological Survey

Contact_Position: GIS Specialist

Contact_Voice_Telephone:
508-548-8700 x2315

Contact_Facsimile_Telephone:
508-457-2310

Contact_Electronic_Mail_Address:
sackerman@usgs.gov

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: Grid Cell

Row_Count: 4688

Column_Count: 9071

Vertical_Count: 1

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Geographic:

Latitude_Resolution: 0.000001

Longitude_Resolution: 0.000001

Geographic_Coordinate_Units: Decimal degrees

Planar:

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: row
and column

Coordinate_Representation:

Abscissa_Resolution: 0.000018

Ordinate_Resolution: 0.000018

Geodetic_Model:

Horizontal_Datum_Name: North American Datum
of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137.000000

Denominator_of_Flattening_Ratio: 298.257222

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Depth_System_Definition:

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: hls10x360geo

Attribute:

Attribute_Label: ObjectID

Attribute_Definition: Internal feature
number.

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain:

Sequential unique whole numbers that are
automatically generated.

Attribute:

Attribute_Label: Value

Attribute:

Attribute_Label: Count

Overview_Description:

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological
Survey

Contact_Person: Larry Poppe

Contact_Position: Geologist

Contact_Address:

Address_Type: mailing and physical
address

Address: 384 Woods Hole Road

City: Woods Hole

State_or_Province: MA

Postal_Code: 02543-1598

Country: USA

Contact_Voice_Telephone: (508) 548-8700 x2314

Contact_Facsimile_Telephone: (508) 457-2310

Contact_Electronic_Mail_Address:
lpoppe@usgs.gov

Resource_Description: Downloadable Data

Distribution_Liability:

Although this data set has been used by the USGS, no
warranty, expressed or implied, is made by the USGS as to the accuracy
of the data and/or related materials. The act of distribution shall not
constitute any such warranty, and no responsibility is assumed by the
USGS in the use of these data or related materials.

Any use of trade, product, or firm names is for descriptive
purposes only and does not imply endorsement by the U.S. Government.